Drive system for honeycomb core machine



Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR HONEYCOMB CORE. MACHINE Filed June 29, 1962 9 Sheets-Sheet l FIG. I

lI -III I D lII -III l U III-I'll l u Ill-IIII u 0. s. HARDING ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE; SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29, 1962 9 Sheets-Sheet 2 INVENTORS.

F. H. ROHR E. M. EY W. F. H H D. S. HARD! a m m iz f ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29, 1962 9 Sheets-Sheet 3 g 9 m m INVENTORS.

BY D. S. HARDING ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,

DRIVE SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29, 1962 9 Sheets-Sheet 4 2 INVENTORS.

F. H. ROHR E. M. LACEY W.F. RETHWISH D. S. HARDING ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR nomavcoms CORE MACHINE Filed June 29. 1962 9 Sheets-Sheet 5 1 243 24 FIG 5 223 I 2 w? 24 230 258 o 232 229 a 5 k 2a! 225 2 2 226 25/ FIG. IO

I9 200 99 20b I02 8 I00 FIG. 8 20 ll @Q I05 D. S. HARDING ATT RNEY Dec. 29, 1964 F. H. ROHR ETAL 3,153,742

DRIVE SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29, 1962 9 Sheets-Sheet 6 INVENTORS.

H. ROHR M. LACEY RETHWISH BY HARDING ATTORNEY E. W. D.

Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29, 1962 9 Sheets-Sheet 7 INVENTORS.

F. H. ROHR E. M. LACEY w. F. RETHWISH FIG. I8 D. s. HARDING ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR HONEYCOMB CORE MACHINE Filed June 29. 1962 9 Sheets-Sheet 8 INVENTORS.

E H. ROHR E. M. LACEY W. F. RETHWISH D. S. HARDING ATTORNEY Dec. 29, 1964 F. H. ROHR ETAL 3,163,742

DRIVE SYSTEM FOR HONEYCOMB com: MACHINE Filed June 29, 1962 9 Sheets-Sheet 9 Ill @12/ E N v; n I J 256 i I F/G. 22 O 1 H 248-" 9 :1! O

299- FIG. 20

INVENTORS.

276 RH ROHR E.M.LACEY, W.F.RETHWISH BY D.S.HARDING arid...

ATTORNEY United States Patent Ofilice Patented Dec. 29, 1984 3,1tl3,742 DRIVE SYSTEM ll tilt HENEY (MB CORE MACHENE Fred H. Rohr, San Diego, Elbert M. Lacey, Chula Vista,

William F. Rethwish, National City, and Dale S. Harding, Chula Vista, (Salli, assignors to Ruhr Corporation,

Chula Vista, Callil, a corporation of California Filed June 29, 1962, Ser. No. 267,162 19 Claims. (El. 2l9--82) This invention relates generally to apparatus for fabri eating honeycomb core and more particularly to a drive system having particular utility when used to drive the welding wheel and electrode and indexing pin movements comprising the honeycomb core fabricating apparatus disclosed in the copending application for Novel Framework for Honeycomb Core Machine, Serial Number 103,589, filed April 17, 1961 now Patent No. 3,077,533.

The aforesaid Welding wheel and electrode and indexing pin movements together with the aforesaid novel framework and the drive system as herein disclosed and claimed comprise a welding system such as disclosed and claimed in the copending application for Welding System for Honeycomb Qore, Serial Number 207,163, filed June 29, 1962, or" which this patent application is a continuationin-part. L

Although not limited thereto, the drive system of the present application and the apparatus disclosed in the aforesaid copending applications are particularly well suited for use in providing the basic welding pin, wheel, and core shuttling movements and welding operations disclosed and claimed in the copending application of Fred H. Rohr for Method and Apparatus for Fabricating Honeycomb Core, Serial Number 846,903, filed October 16, 1959, now Patent No. 3,679,487.

Many manufacturing processes-such as welding require that several parts be brought together and assembled precisely at the Work station; held at the work station is such assembled relation for the duration of the welding period; and then shuttled out of the work area to make way for successive parts to be introduced, assembled, and acted upon within the work station. A sitnation of this type arises in the fabrication of so-ealled honeycomb core that is widely used in airplanes for low-weight, high-strength structure. In the fabrication of this honeycomb core, strip feed and corrugation means operate in timed relation cooperatively with internesting electrode and indexing pins which serve to move sections of corrugated metal ribbon or strips into juxtaposed alignment so that the troughs of one strip rest on the crests of another strip preparatory to the welding or" the same together. The strips are then held in this position While coacting electrode pins and welding wheels pass the welding current through the abutting and juxtaposed nodes of the adjacent crests and troughs to thus weld the same together and form cells of the honeycomb core. When selected crests and troughs have been welded together, the electrode pins and Welding members are withdrawn from the thusly formed cells and, following the shuttling of the core by the indexing pins, re-inserted and re-applied as the process is repeated, as necessary, to CO1 rplete the core.

For a completely satisfactory result, providing high quality honeycomb core, the corrugating and juxtapositioning of the strip sections must be very precise, the abutting nodes to be welded must be critically positioned above the electrode pins, and the welding wheels must be caused to track precisely above and along the electrode pins in order to properly pass the Welding current therebctween and through the abutting nodes, all in a manner to form optimum Welds in the nodal areas while avoiding burning of the thin stainless steel ri bon material at the sides of the nodes. To this end, the pressure, movement, and electrical contacting of the welding members, particularly the electrical circuit continuity through the welding wheels nrust be critically controlled; and the precision positioning, alignment, and relative movement of parts must persist repetitively in the cell-to-cell formation throughout the length and width of the core. It follows therefore, that the Welding members per se must be adapted to maintain structural integrity and fixed operative relationships as Well as electrical circuit continuity during the welding proces and, to this end, the framework structures and surfaces that support and guide the positioning and welding members must be strong, sturdy, and carefully aligned. Tliese framework and supporting structures, moreover, like the welding membcrs per so, must be capable of retaining their relationship during the Welding process and, in addition, repetitively retain such structural integrity and relationship of the parts during the shuttling and other movements pre paratory to Welding of successive sections of the ribbon material.

In addition to the above critical structural functional relationships and parameters affecting the success of the core fabrications, much depends upon the precision With which the welding wheel and electrode and indexing pin movements are executed repetitively. When done properly, i.e., precisely and positively, this not only assures the feasibility of automatic and/ or programming operations of the core machine and, hence, expeditious fabrication of the core, but assures a uniform quality of cell formation and spacing in successive groups of cells, and avoids damage to the cell walls upon re-entry of the pins into previously formed cells.

In accordance with the present invention, improvements are provided in apparatus for fabricating honeycomb core from corrugated metallic ribbon wherein (A) the core, in the process of fabrication: is supported on internesting electrode and indexing pins mounted for axial movements into and out or" the cells of the core; is built up layer by layer of the corrugated ribbon which is welded to the core by current passed between the electrode pins and Welding wheels which sweep over aligned and abuttingribbon and core nodes supported on the electrode pins; and is shuttled by the indexing pins as the same are moved in a closed rectangular path selectively to either side of the electrode pins and wherein (l3) these wheel and pin movements so critically essential to the proper fabrication of quality core are effected by a novel drive system therefore having provision for effecting the required precision of movement of the parts and cornponents of the core machine. More particularly, the drive system comprises, among other elements, an electric motor driven actuator which is mounted for yieldable movement about its drive axis and having cable driving connections with the part or component to be moved, or driven. The driven part is thusly moved selectively against one or the other of a pair of spaced stops positioned in desired end limit positions of movement thereof, this being accomplished without deenergizing the motor. When the stop is reached, continued operation of the motor further tensions the cable and causes rotation of the actuator about its drive axis and against the biasing force of its yieldable mount. When the actuator has rotated a predetermined amount in either direction about its drive axis, a switch is actuated to deenergize the motor and to close a switch for effecting further sequential operations of the machine, the motor actuator is a commercially available geared motor device having a well known rnagntic clutchbrake arrangement for ale-coupling the electric motor from its gear train and simultaneously applying a brake to the gear train when the electric motor is de-energized. The actuator is thus locked and held in its rotated position against the biasing return force of its yieldable mlount, thereby to hold and lock the driven part in position against the stop.

The drive system of the present invention thus obviates the difficulties of prior art arrangement wherein failure to reach a stop position may result from several reasons inherent in such arrangements. Hunting may result, for example, in the prior art arrangements, as Where a motor driven part is arranged to open a switch to deenergize the motor upon reaching the end position and the part rebounds from the abrupt stop in such position. The part may also fail to reach the end position, as where the motor is deenergized in anticipation of there being sufficient inertia and overrun to move the part the remaining distance to the stop position.

An object of the present invention therefore is to provide a new and improved drive system for moving a part precisely and positively into position against a stop.

Another object resides in the provision of a new and improved core fabricating apparatus having drive systerms, as aforedescribed, for elfecting the basic welding pin, wheel and core shuttling movements thereof.

Still another object is to provide a drive system having particular utility in effecting the positive and precise movements essential to a core shuttling operation whereby the core is moved by the indexing pins in multiple increments of the spacing between adjacent nodes to thus assure that cells of the core into which the electrode and indexing pins are subsequently reinserted will always be aligned axially therewith, and this being accomplished, notwithstanding the requirement of the indexing pins to shuttle the core in both directions longitudinally of the ribbons of the core.

Yet another object of the present invention is to provide a new and improved machine for fabricating honeycomb core having provision for precise tracking of the wheels across the aligned nodes of the ribbons to be welded together, having provision for parallel relative movement of the wheels and pins parallel to the axes of the electrode and indexing pins, having provision for precise indexing movements of the wheels, pins and core relative to each other, and having provision for assuring circuit continuity and optimum conductivity for the purpose as well as optimum contact pressure of the welding wheels, while also having provision for ready assembly and replacement of parts.

Still other objects, features and advantages of the present invention are those inherent in the novel construction, combination and arrangement of parts comprising the drive system, presently to be described, which has been constructed in accordance with the best mode thus far devised for practicing the principles of the invention, reference being had to the accompanying drawings wherein:

FIG. 1 is a fragmentary view, somewhat enlarged, of a honeycomb core in the process of being welded;

FIG. 2 is an isometric view of a framework which, taken with the components of the drive system, embodies the basic inventive concept of the present invention;

FIG. 3 is a plan view of the machine shown in FIG. 2, certain parts being removed;

FIG. 4 is a view in section of the machine taken along the line 44 of FIG. 3;

FIG. 5 is a fragmentary front view of the machine;

FIG. 6 is an enlarged fragmentary sectional view as seen along the line 6-6 of FIG. 5;

FIG. 7 is a plan view of the electrode pin assembly;

FIG. 8 is a sectional view of the electrode pin assembly as seen along the line 8-8 of FIG. 7;

FIG. 9 is a sectional view of the indexing pin assembly, this view being similar to that of FIG. 8;

FIG. 10 is a sectional view of an indexing pin as seen along the line 1010 of FIG. 9;

FIG. 11 is an enlarged side elevation of the wheel assembly disclosed in FIG. 4, certain parts being broken away to disclose features of construction and arrangement of parts;

FIG. 12 is a front view of the wheel assembly disclosed in FIG. 11;

FIGS. 13 and 14 are top fragmentary views of wheel assemblies showing alternative wheel spacing arrangements;

FIG. 15 is a side elevation of a wheel sub-assembly;

FIG. 16 is a sectional view of the wheel sub-assembly as viewed along the line 16-46 of FIG. 15;

FIG. 17 is a sectional view of the wheel sub-assembly as viewed along the line 17-17 of FIG. 15;

FIG. 18 is a fragmentary exploded view of the wheel sub-assembly of FIG. 15;

FIG. 19 is an exploded view of the mount for the wheel sub-assemblies;

FIG. 20 is an end view of a motor actuator unit;

FIG. 21 is an exploded view of the motor actuator unit of FIG. 20; and

FIG. 22 is a plan view of the switch mounting plate of the actuator unit.

Referring now to the drawings for a more complete understanding of the invention, and first more particularly to FIGS. 2 to 4, there is shown thereon a honeycomb core fabricating machine which is functionally equivalent to that disclosed and claimed in the aforesaid copending application of Fred H. Rohr, Serial Number 846,903, that is to say, both machines have the same basic components and the same basic movements. Thus, both machines comprise a welding wheel assembly or welding head generally designated 10, an electrode pin assembly 11, an indexing pin assembly 12, and a supporting framework generally designated 13.

A core in the process of fabrication on the machine is generally designated 14 and is built up from an endless corrugated ribbon 15 which is supplied from a source (not shown) such as the strip feed and corrugating apparatus disclosed and claimed in the copending application of Elbert M. Lacey, Jr. for Method and Apparatus for Feeding Metal Strips, Serial Number 78,720, filed December 27, 1960, now Patent No. 3,123,125. The ribbon so supplied is received by way of a suitable chute or slide 9 and a wine glass shaped feed control device 16 which forms a hopper in its upper portion into which the ribbon 15 may fall into one or more loops such as indicated at 17. Feed control device 16 also has a narrowed throat portion 18 providing a restricted opening which approximates the thickness of the corrugated ribbon, that is to say, the dimension corresponding to the depth of a trough or the height of a crest, as the case may be. The restricted opening serves to keep the ribbon supplied to the core under sufficient tension, short of stretching and deforming the same, such that the ribbon nodes fall naturally into alignment with the confronting nodes of the previously formed core layer. On leaving the throat 18, the ribbon is fed and guided outwardly of the device 16 through the open bottom thereof in either direction longitudinally of the core and into what becomes the upper layer of the core as the same is shuttled in either direction to the right or to the left of the machine.

The electrode pins 19 move axially into and out of what constitutes the upper row of completed cells of the core 14, and the indexing pins 21 move axially into or out of what constitutes those cells which are being newly added to the core upon welding of the ribbon 15 thereto.

Electrode pins 19 which in the specific case, as shown, may be 12 in number, are precisely formed and precisely mounted and spaced in a header member 20 to which they are suitably secured as by being potted in a body of suitable plastic such as an epoxy resin molded within the member 20. When so formed, the electrode fingers or pins 19 closely fit the cell configuration, as may be seen in FIG. 1, but may be freely moved axially thereof into or out of the cells of the core 14. Indexing pins 21 are similarly formed and precisely spaced and mounted in a header member 2.2 comprising the indexing pin assembly 12.

Electrode pins 19 lie generally within the plane of the cells of the core 14 formed by the previous welding thereto of a length of ribbon 15 extending along the length of the core. The indexing pins 21 are disposed in internesting relationship with the electrode pins 19 and are disposed generally in a plane spaced one-half cell width above the plane common to the electrode pins. As otherwise expressed, the indexing pins are disposed generally in a plane of those cells Which are being newly added to the core to form the upper layer of cells thereof.

Both the electrode and indexing pins are mounted for movement axially thereof into and out of the cells of the core, and the electrode pins when so inserted into the core, are in supporting relation with respect thereto, the core being depended from these pins and supported, at least in part, therefrom. The indexing pins 21, on the other hand, when inserted into position on the core, are disposed beneath a section of the corrugated ribbon 15 which is to be welded to the core and, consequently, do not initially provide a support function for the core. When the welding of this ribbon section has been completed and the same is secured to the core, and when the electrode pins have been withdrawn axially from the core, the core is then supported by the indexing pins such that the core may be shuttled by movement of the indexing pin assembly 12 to the right or to the left, as the case may be.

With the pants in the positions as shown in FIG. 2, the machine is so set up that upon being set in operation, the core 14 would be shuttled in successive increments of 12 cells each to the right. Assuming, for example, that the welding wheel assambly has just returned from a sweep across the ribbon section disposed above the pins 19 and 21 such that this ribbon section has been welded to the core, the electrode pins 19 are then withdrawn from the core, or may have been withdrawn from the core upon the return sweep movement of the welding wheel assembly 11). On removal of the electrode pins 19 from the core, the same is supported by the indexing pins 21 and may be shuttled to the right as a unit with the indexing pin assembly 1.2. On shuttling the core, an additional length or section of ribbon is withdrawn from the feed control device 16 and assumes a position of alignment with the confronting nodes of the corresponding section of the upper ribbon of the core. The electrode pins are then reinserted into the core beneath the last mentioned ribbon section, following which the indexing pins are withdrawn axially from the core and the assembly 12 returned to the area of the welding station. The indexing pins are then inserted beneath the newly superimposed section of ribbon 15 which is to be welded to the core in the next cycle of operation of the welding machine.

When the core has been shuttled completely to the right such that the last core section of increment of cells at the extreme left end of the core have been formed at the welding station, both sets of electrode and indexing pins 19 and 2,1 are withdrawn axially from the core and the core is lowered by one-half cell width following which the pins are again inserted into the confronting cells of the core. The wine glass control device 16 is then moved from the position shown to the right side of pins 19 and 11 into a position comparable to that disclosed on the left side of the pins, that is to say, device 16 will be similarly supported on stripper bars 23 and 24 between which the core 14 builds up layer by layer as the same is lowered one-half cell width at a time from the pins 19 and 21. spaced dowel pins 26 which are adapted to be received in openings 27 in stripper bar 23 to assure proper positioning of the device 16 on the stripper bars on either ide of the pins 19 and 21.

As the device 16 is moved to the right side of the pin The base of device 15 carries a pair of assemblies, an additional length of the ribbon 15 is withdrawn therefrom and doubled back over that portion which has just previously been welded to the core, and this new section of ribbon falls naturally into alignment therewith, node for node, as aforedescribed. The machine is then in position for shuttling of the core by increments to the left to add the next layer of cells to the core. When this layer has been completed, the extreme right end section of the core is positioned at the welding station and the core is again lowered one-half cell width and feed control device 16 returned to the left side of the pins 19 and 21, as shown, to thus complete an overall cycle of operations of the machine.

This overall cycle thus, by way of review, includes shuttling of the core in one direction over the length thereof to complete one row of cells of the core followed by shuttling of the core in the reverse direction and over the length thereof to form a second row of cells of the core. The core so fabricated, may be made to any desired length and may be built up row-by-row to any width within the space limitations of the environmental surroundings of the machine. When desired, moreover, the machine may be shuttled continuously in either direction and the core returned upon itself to form an endless belt.

Referring now more particularly to FIG. 1, it may be seen that the corrugated ribbon 15 has flattened troughs 28 and crests 29 which form aligned and abutting nodes 28, 29 of adjacently disposed and oppositely corrugated ribbon sections. As otherwise expressed, these adjacent and oppositely corrugated ribbon sections are displaced relative to each other by one half the spacing between corrugations, or by one half the length of a cell as measured longitudinally of the core, with the result that the crests of one section are aligned and abutted with the troughs of the other. Upon welding together of these abutting nodes, generally diamond-shape cells of square configuration are formed, but for the flattened crests and troughs which tend to give the cells a hexagonal configuration.

The aligned and abutting nodes 28, 29 to be welded are juxtaposed and supported on the electrode pins 19 whose upper surfaces are appropriately matched to conform with the under surfaces of the crests 29. The upper surfaces of the adjoining troughs 28 are electrically engaged by the welding wheels 30 whose peripheral rim portions provide an engaging surface area 31 whose width may be of the order of A the nodal width. Thus, in a specific case, the wheel rim perimeter 31 may be .010 inch wide and the nodal width approximately 0.04 inch. This allows for limited wandering or deviation of the wheels 3ft from the intended welding swath to be laid down thereby when the welding current passes between the wheels and electrodes as the wheels sweep along the aligned and abutting nodes and across the adjacent ribbon sections to be welded together.

In order to hold the welding swath or track alongthe nodes substantially within the allotted dimensional width, the wheels must be precision formed and rotatively mounted, and the alignment of the abutting nodes likewise must be precisely arranged. This, in turn, requires that the spacing between pins, both indexing and electrode, be accurately established and maintained repetitively in the course of the several pin and wheel movements which must take place with each cycle of operation of the machine.

The electrode pins, as aforenoted, serve to align the crests 259, but it is one of the functions of the internesting indexing pins to assure that the abutting troughs 28 are properly aligned and juxtaposed therewith and this, in turn, assures that subsequently, the electrode pins will be properly received into the cells previously formed about the indexing pins.

The core soformed from cell to cell and layer to layer comprises an integral length, or spliced continuous length of ribbon 15 which, as aforedescribed, is doubled back upon itself at each end of the core as indicated at 32, as each new layer of cells is to be added to the core. When so doubled back over the indexing pins 21, as shown in internesting relation with respect to the electrode pins 19 in FIG. 1, the precision forming of the corrugations in the ribbon 15 and the precision forming and spacing of the internesting pins combine to assure that the abutting nodes will juxtapose and align relative to each other and with respect to the electrode pins. The end result is high quality core of uniform and consistent cellular configuration and of virtually limitless length and breadth.

The uniformity and consistency of the welds also contribute to the quality and strength of the core and this, again, depends on the extent to which the internesting pins effect the desired alignment, abutment and genenal juxtaposition of the nodes with respect to the electrode pins. The tracking and pressure of the welding Wheels are further factors contributing to the achievement of satisfactory welds, as are the parameters of the welding circuit and system as hereinafter more fully described.

It sutfices to state with reference to FIG. 1 that the electrode pins 19 are formed of highly conductive material and precisely spaced and embedded in plastic insulation in the head 20, these pins therefore being insulated from each other. Each pin 19 is separately brought out and connected to a transformer secondary winding 33, the other terminal of which is connected to the support 36 for the coacting electrode wheel 39, as indicated schematioally in FIG. 1. The indexing pins are similarly embedded in head 22 and thus precision spaced and electrically insulated but need not be so insulated or formed of highly conducting material since they have no electrical function, the indexing pins preferably being formed of cold rolled steel.

Each electrode pin 1% and its associated coacting electrode wheel 30 are thus connected in circuits individual thereto in series with a secondary transformer winding 33. In the specific disclosure of 12 welding wheels and 12 electrode pins there preferably are employed 4 transformers such as the transformer 34 disclosed which has a primary winding 35 and 3 secondary windings 33. By reason of this arrangement, the welds laid down by each Wheel are rendered independent of any circuit variations such as may be experienced by the circuits individual to the other wheels. In prior art arrangements wherein the wheels may be connected in series or in parallel arrangements, variations in the node contact pressures or Wheel contact pressures produce variations in the resistance of the welding current paths wtih the result that an unfavorable weld condition experienced by one of the number of series connected wheels may lessen the welding current and prevent satisfactory Welds by the others or, in the case of parallel connected wheels, the welding current due to a burning through or shorting of one of the wheels may reduce the current to others below that required for satisfactory welds.

Referring now to more particularly to FIGS. 6 to 10, it will be seen that the electrode pins 19 and indexing pins 21 are formed and shaped identically. As best seen in FIG. 10, the pins are formed from square stock, the upper corner of which is removed to provide a top surface 90 which precisely fits the under surface of a node 29 (FIG. 1), of the corrugated ribbon 15. Similarly, the upper diagonally directed surfaces 91 precisely fit the diagonally directed undersides of the ribbon adjacent the node 29. Surfaces 91, however, are undercut as at 92 to provide longitudinal grooves for receiving protrusions in the ribbon when the same is perforated, as at the time of forming the corrugations in the ribbon. The lower corner of the square stock is removed to a greater extent than in the case of the upper corner with the result that the lower surface 93 is wider than the upper surface 90, and clearance grooves 94, similarly formed in the lower diagonal surfaces 95, terminate in the surface 93. The remaining portions of surfaces 95 precisely fit the adjacent cell walls to thus assure precise forming of the cells but the material removed in forming bottom surface 93 and grooves 94 provides clearance between the pin and the lower walls of the associated cell. This clearance not only assures freedom of movement of the pins within the cells, and particularly with respect to perforation protrusions which are directed alternately upwardly and downwardly as the ribbon is doubled back and forth upon itself, but the clearance also permits use of ribbon which may be varied in thickness, as required, to provide various strength patterns in the fabricated core.

A ribbon stop 96 is undercut to fit the upper surface of the pins as disclosed in FIG. 10, one of these stops being used for each indexing pin 21 to which it is secured as by rivets 97. As may best be seen in FIG. 9, ribbon stops 96 are so positioned on the indexing pins such that one end of a stop extends into the potting resin 22a which fills the recess 98 in the header member 22 for holding the indexing pins 21. The ribbon stops have suflicient length along the indexing pins such that the opposite ends of the stops lie flush with the inner face of stripper bar 24, as indicated by the dashed line at FIG. 6. As will appear more fully as the description proceeds, an adjustment of the support frame for the indexing pins is provided to assure that the ribbon stops are thus properly aligned with stripper bar 24.

Each of the electrode and indexing pins is reduced in diameter as at 99. This has no utility in the case of the indexing pins, but in the case of the electrode pins, serves to receive a ferrule 100 which, in turn, has a conductor cable 101 secured thereto. Ferrule 169 is secured, as by brazing, to the electrode pin, and a suitable tube of insulation 192 preferably covers conductor 101 and extends over the exposed end of the ferrule. Potting plastic 2tla for retaining the electrode pins fills recess 98 in the header member 2t for holding electrode pins 19 and has a rearwardly extending portion 201) which serves to insulate and support the cable ferrules 190.

Each of the electrode and indexing pins is tapered to a point 103 in order to assure free entry of the pins into the cells of the core, and the tips of the electrode pins are chrome plated, as indicated at 104 to avoid premature wear of the soft copper pins as the same move against the knife edge thin edges of the relatively hard stainless steel ribbons.

As may be seen in the drawings, the electrode and indexing pin holders 2t) and 22 per se are identical and each has spaced openings 105 to receive suitable bolts, screws, or like fasteners, such as fasteners 106 (FIG. 5 to secure the holders to their respective supports 63 and '59 respectively. I

The internesting electrode and indexing pins 19 and 21, when inserted within the cells of the core, lie over the spaced stripper bars 23 and 24 and bridge the same, as best seen in FIG. 6. The bars 23 and 24 are notched as indicated at 1&7 (FIGS. 5 and 6) to receive the electrode pins and support the same in mutually spaced relation. Although the electrode fingers thus contact the steel stripper bars, the low resistance of the fingers constitutes a preferential path for the welding current through the fingers. The indexing pins 21 lie above the electrode pins in internesting relation therewith, but lie above the stripper bars and clear the same to thus permit the indexing fingers to shuttle longitudinally of the bars. Thus, the core, which occupies the space between the dashed lines (FIG. 6), is freely shuttled longitudinally of the bars by the indexing fingers disposed within the cells of the core, the electrode pins, of course, being withdrawn from the core at the time of the shuttling movement.

35, however, are formed of highly conductive metal such as copper whereas the member 38 preferably is formed of the less conductive steel. It is preferred therefore that the transformer lead or cable 108 be secured, as by brazing, directly to the copper member 36 which, for this purpose, has a terminal portion 139 to which the cable is connected.

Each wheel 30 is secured to its support member as by means of a countersunk screw 110, which in the manner of mounting of screw 37, has a countersunk opening 111 provided therefor in member 36. The wheel has a large central opening 112 which receives the shoulder or hub 113 of a steel washer-shaped nut 114 upon which the wheel is journalled for rotation. The inner face 115 of nut 114 is recessed at 116 which thus reduces the area of the bearing surface afforded by face 115 in sliding engagement with the hub face 117 of the wheel. The diameter of bearing face 115, however, is significantly large and serves to prevent wobble of the wheel on the hub bearing surface 113 when the opposite hub surface 113 of the wheel is moved against the inner surface 119 of member 36, as by tightening screw 11% into the threaded opening 120 provided therefor in nut 114. Face 119 is also recessed as at 121 to reduce the bearing area of the wheel on face 119, particularly in view of these surfaces both being copper. The area of contact or electrical engagement of surfaces 118 and 119 is ample, however, to optimumly pass the welding current between the wheel and support member 36, and the anti-wobble bearing arrangement assures electrical circuit continuity between these parts.

As may best be seen in FIGS. 17 and 18, the lower end 122 of member 38 is reduced in thickness and is shaped similarly to the hub portion of wheel 30, having a central opening 123 for receiving the hub 113 of a nut 114, and having opposite faces 124 and 125 for respectively engaging faces 115 of nut 114 and face 119 of member 36. A recess 126, concentric with the axis of hub 113 and screw 37, is provided to reduce the bearing area of face 119 of member 36 in engagement with face 125 of portion 122 of member 38, and the reduced face 115 of nut 114 similarly provides a limited bearing area in engagement with face 124 of member 38. Screw 37, as in the case of screw 110, engages its associated nut 114 to move these bearing surfaces into face adjacency.

Referring now more particularly to FIGS. 15 and 17, each member 38 carries a threaded pin 41 which is threaded therein and locked thereto by a nut 127. Pin 41 terminates in a bifurcated member 128 which, in turn, carries an adjustment screw 129 against which a compression spring assembly 42 is urged, the other end of this assembly being urged against wheel pivot member 36 with the result that wheel 30 is urged by its spring assembly to move in a downward direction.

This downward movement of the wheel is limited and adjustable by a second threaded pin 130 which is threadedly received in member 38, locked thereon as by a nut 127, and passed therethrough to engage a stop 131 in the form of an angularly bent upstanding portion of member 36.

A second angularly bent upstanding portion 132 of member 36 has a recess 133 formed therein which serves to seat the tip of the tapered pin 134. Pin 134 is enlarged as at 135 and 136 to provide a seat for compression spring 137 of the spring assembly 42 The other end of spring 137 is similarly seated on shoulders 138 and 139 formed on a tapered pin 140 which seats in the cupped end of adjustment screw 129. The shank 141 of pin 140 is drilled out as at 142 to slidably receive the shank of pin 134 therewithin to thus make provision for pivotal movement of member 36 about the axis of screw 37 while retaining the spring assembly 42 in compressive engagement with screw 129 and seat 133.

Adjustment of stop screw 130, as aforedescribed, limits the downward pivotal movement of wheel 30 and its support 32, and adjustment of screw 129 determines the extent of initial compression of spring 137 in urging the member against the stop screw 139. The contact pressure with which each wheel 39 engages the ribbon nodes to be welded as the wheel moves yieldably thereagainst may thus be accuratcd predetermined andpreset, working directly with the wheel sub-assembly unit as disclosed in FIG. 15.

Elongated clearance openings 143 are provided in each member 38 to receive suitable fasteners 144 (FIGS. ll to 14) for securing the same to an adapter plate 145 and intermediate sheet id of insulation material such as Micarta. The heads of screws 144 actually engage retainer pieces 146 having insulation pieces 147 which, in turn, engage members 355 and bridge the elongated openings 143 therein. Screws 144 which clear the openings 143 may thus be tightened to clamp members 38 together as a unit in adjusted positions on adapter plate 145 without connecting the same electrically together through the adapter plate.

It will be understood that the wheel sub-assemblies will be made in different sizes in accordance with the various cell sizes of honeycomb core to be fabricated and, accordingly, the parts may be smaller, note the reduced thickness of parts 38 in FIG. 13 as compared to the same parts as in FIG. 14, and the wheel sub-assemblies may be closely or widely spaced on the adapter plate' In FIG. 13, for example, a large number of thin, closely spaced wheel assemblies, spaced in accordance with the spacing between cells of the core to be fabricated, are employed in an arrangement in which welding is to ocour in only one direction of sweep of the wheels over the abutting ribbon nodes. In FIG. 14, by way of contrast, the parts are larger and the spacing between the wheel sub-assemblies is greater, the arrangement being one in which welding is to occur on both passes of the wheels back and forth across the abutting ribbon nodes, the wheels, however, being shifted laterally by one cell width, after passing across alternately spaced nodes, in order to weld the intermediate nodes on the return stroke of the wheels.

The adapter plate 145 is secured as by four screws 148 to a movable support member 39 (FIG. l9) which, for this purpose, has four threaded openings 149. Member 39 is mounted on a fixed head member 44 for raising and lowering movements, and also for side to side movements, of the welding wheels with respect thereto, these movements being accomplished by means of an interfitting centrally disposed member 150. To this end, member 39 has rearwardly extending upper and lower ears 151 and 152., respectively, which ears have longitudinally extending openings 153 for receiving pins 154, in turn, receivable in apertures formed therefor in upstanding and depending ears 155 and 156, respectively, on member 150. In assembling members 39 and 150, the same are first moved together with pins 154 being removed. Once assembled, the pins are inserted thru the openings 153 and inserted as with a press fit within the openings in cars 155 and 156, or by threaded engagement therewith.

The upper and lower surfaces of member 156 similarly carry upstanding and depending pins 43 which are secured thereto after first being passed through openings 158 provided therefor in forwardly extending ears 159 and 166 on member 44. This is done, of course, when members 4 and 159 have first been fit together such that their pin receiving openings are aligned.

When members 33, and 44 have been assembled, as aforedescribed, member 39 and the wheel sub-assentblies supported thereon may be shifted laterally and slidably along pins 154 and relative to members 150 and 44 which are constrained to vertical movement relative to each other slidably along pins 43. This lateral movement is effected as an incident of the movement of the members 39, 156 and 44 as a unit, namely, welding head 10, as the same moves to forward and return end limit positions axially of the unit support rods 70 and '71 which are suitably secured to fixed member 44 and bosses 161 thereon, as by fasteners 162 (FIG. 11). Members 39 and 154 have openings 163 and 164 for freely receiving these bosses, as best appears in FIGS. 11 and 19.

To effect the lateral shift, member 39 carries an upstanding p-in'165 which is adapted to be received in the bifurcated end 166 of a bell crank 167 which is pivotally mounted on member 44 by means of a pin 168. The other end of the bell crank has an opening to receive the upturned end of a long rod 169, the same being secured therewithin by a cotter pin 170. Rod 169 also freely passes through an apertured bracket 171 which is suitably secured as at 157 to frame member 68.

Collars 172 and 173 are secured to rod 169 fore and aft of bracket 171 and spaced with respect thereto such that, as the welding head and welding carriage frame, generally designated W, move forward, rear collar 173 is ultimately stopped by bracket 171, and this causes bell crank 167 to be pivoted counter clockwise about pin 168 as the forward movement is completed thereby causing member 39 and the wheel sub-assemblies supported thereon to be shifted to the right as viewed in FIG. 19. On the return trip, collar 172 is stopped by the bracket, the bell crank pivots clockwise, and the shift of member 39 and the wheels is then to the left. thereby completing the shifting cycle.

An offset leaf spring 174 suitably secured to member 44 as at 175 engages the rod-coupled end of hell crank 167 such that it moves with a snap action into the two shift positions provided, these being determined and set precisely by adjusting screws 176 (one only being shown) which are provided at each end of member 39. These screws extend thru ears 152 for engagement, respectively, by the ears 156 of member 150.

When the lateral shift of the wheels is not required, as when the welding is accomplished entirely on the forward pass of the wheels, the collars 172 and 173- are simply spaced a greater distance from bracket 171 such that bell crank 167 is not activated by movement of welding carriage W.

Member 150 has a bifurcated bracket 89a secured thereto (FIG. 19) as by suitable fasteners 175 and provides a pair of spaced upstanding lugs having aligned openings 177 for receiving a pivot pin 80 (FIG. 2). By this means wheels 30, their adapter plate 145 and members 39 and 150 may thus be lowered relative to the fixed plate 44 to bring the Wheels into engagement with the abutting nodes, and further lowering movement of the member 39 after the wheel engagement is thus established, causes predetermined compression of the spring assembly 42 to thus provide a required contact pressure of the wheels on the associated nodes.

The success of the welding operations and the quality of the fabricated core depend in large measure upon the precision with which the welding head 11? and the electrode pin and indexing pin assemblies 11 and 12 may be moved repetitively to engage the ribbon and core and to shuttle the core following the welding of each series of aligned and abutting nodes. The precision with which these movements may be executed depends, in par-t, on the motor drive system hereinafter disclosed. The precision of these movements also depends upon the frame work support for the assemblies 10, 11, and 12. This framework 13 comprises a main frame and several subframes presently to be described, as may best be seen by reference to FIGS. 2 to 4.

The main frame comprises two basic structural members in the form of a pair of spaced parallel tubes 45 and 46 the inherent rigidity and torsional strength of which provides basic support for the outer structural members of the machine, and by reason of the telescopic nature of the tubes serves to slidably support the subframe designated I upon which the indexing fingers 21 are mounted for axial movement, as will presently appear.

The structure for supporting the tubes 45 and 46 with respect to a support surface such as a table top or floor surface may comprise a base member 8 and one or more uprights 51 (FIG. 4) which support the transformers 34. The uprights support a pair of U members 47 the spaced legs of which provide space support for tubes, there being one such U member for each of the tubes. The extremity of each leg of U member 47 is apertured to receive its engaging tube and each leg is severed along a diameter of the tube as indicated at 48 to provide complementary gripping surfaces to clamp the leg to the tube, the severed extremity 49, for this purpose, being secured to the main leg portion as by suitable threaded fasteners 50. This manner of clamping various structural members to the tubes and to like members of circular cross section is employed throughout the several parts of the framework and, accordingly, this clamping feature will not again be described in detail.

Slidably supported within tubes 45 and 46 are a pair of elongated rods 52, and 53 respectively which extend beyond either end of the tubes. At the rear end of the tubes, rods 52 and 53 are interconnected by a cross member 54 which has openings for receiving the rods interfittingly therewith and has substantial width axially of the rods so as to effect a rigid rectangular subframe therewith, hereinbefore generally designated I. This rigid rectangular subframe is completed at the forward extended ends of rods 52 and 53 by a second rigid rectangular frame designated S and comprising a pair of depending members 55 and 56 which are respectively clamped to the ends of rods 52 and 53. These depending members, in turn, are rigidly interconnected as by fasteners 178 to a pair of spaced parallel rods 57 and 58 (FIG. 5).

Slidably supported on rods 57 and 58 is an inverted U member 59 whose legs are suitably apertured to slidably receive the rods. The base of slide 5') is suitably formed to provide for interfitting engagement with indexing pin head 22 to which it is preferably secured detachably, as aforedescribed (FIG. 5). The spacing between tubes 45 and 46 and rods 52 and 53 is such that slide member 59 and the indexing pins and head supported thereon may be moved fully to either side of the electrode pins when the same have been withdrawn axially from the indexing pins, thereby to shuttle the core 14 by an increment of 12 newly formed cells of the core. This shuttling space to the left of the machine, with the parts in position as shown in FIG. 2, is occupied by the ribbon feed control device 16 and, accordingly, the shuttling of the core, as shown, occurs to the right of the machine. When the indexing head 12 has been moved into this shuttling space on the right of the machine, the subframes I and S are readily moved as a unit forwardly of the machine by reason of the free sliding movement of the rods 52 and 53 in the spaced parallel tubes 4-5 and 46. This movement of these subframes causes axial Withdrawal of the indexing pins 21 from the core, and the indexing head and its slide support 59 may then be slidably moved along rods 57 and 58 to restore the indexing head to the welding station at which time the subframes I and S may be moved as a unit rearwardly of the machine for re-engagement of the indexing pins with the core and internesting engagement with the electrode pins 19.

Each of the stripper bars 23 and 24 at each end'thereof, has secured thereto and extended upwardly therefrom a member 616, the upper end of which is formed as heretofore described for clamping engagement with the associated tubes 45 and as, as the case may be. This clamping arrangement readily permits of adjustment of the stripper bars 23 and 2.4 axially of the tubes 45 and 46 to thus accommodate between the stripper bars variable core thicknesses within limits imposed by the overlapping length of the indexing and electrode pins. It will be understood, moreover, that indexing and electrode 13 heads 11 and 12 having different finger lengths may be installed on the machine to thus provide for variable core thicknesses, as measured in terms of the width dimension of the ribbon 15, of the order of upwards of inches.

Reieiring now particularly to FIG. 4, it will be seen that a pair of members 179 and 180 secured respectively at both sides of the machine to the ends of stripper bars 23 and 24, and to their associated support members 60, have angularly bent portions 181 and 182 which serve to support a pair of elongated longitudinally extending bars 133 and 184. These bars, like stripper bars 23 and 24, define a vertical channel through which the fabricated core builds up row by row of the cells of the core Members 185 and 166 are secured respectively to bars 183 and 184 and depend therefrom. and terminate in longitudinally extending bars 187 and 138. A core support 139, such as a block of plywood, is disposed beneath the core 14 during fabrication of the first several rows of cells and is perforated in simulation of the spacing between the cells to receive pins 190 which bridge the bars 187 and 188 and slide therealong as the core is shuttled from side to side. When the core has been built up sufiiciently to clear the bars 183 and 184, the same may be used to support the pins 190, the board or support 189 then being removed from the machine. Pins 190 in any event provide support for the core as the same extends beyond the ends of stripper bars 23 and 24 to either side of the machine, and provide the entire support for the core as when both electrode and indexing pins 19 and 21 are withdrawn therefrom.

Support 189 alternatively may be fabricated from a light weight metal member of T cross section to which spaced sheet members 191 are secured substantially as shown.

In the manner heretofore described for the indexing pin subframe I, there is provided a similar subfrarne designated E for the electrode pins 19. Subframe E thus similarly comprises a pair of spaced rods 61 and 62 which, at their forward ends, are interconnected by a cross member 63 to which they are rigidly secured in any suitable manner. Cross member 63 serves to support the electrode pin head 20 to which it is secured preferably detachably by suitable fastener means (not shown) but utilizing mounting holes 165 in holder 20, as aforedescribed. The other end of rods 61 and 62 are interconnected by a cross member 64 to which they are rigidly secured, cross member 64 being generally similar, and its manner of attachment to rods 61 and 62 being generally similar to the construction and arrangement heretofore described in connection with cross member 54 of subframe Ii Subframe E is mounted for free sliding movement and axial movement of the electrode pins 19 parallel to the axes of the tubes 45 and 46 by means of a pair of spaced parallel cross members 65 and 66 which interconnect the tubes and are clamped at the ends thereof to the tubes, the clamping arrangement being as heretofore described in connection with main frame support member 47. Rods 61 and 62 are mounted for free sliding support in openings suitably provided therefor in cross members 65 and 66, these openings being aligned such that the rods in their sliding movements move parallel to the axes of tubes 45 and 46.

Cross members 65 and 66 are generally C shaped and generally depend from the spaced tubes 45 and 46. Cross member 65, however, in that central portion 67 thereof extending between spaced parallel rods 61 and 62 is directed upwardly to provide a clearance space for electrical cables 161 and 168 which individually connect to and terminate at the electrode pins 19 and wheel subasseinblies respectively. A support 67a for these cables conveniently is secured, as shown (FIGS. 3 and 4) to upstanding portions of cross member 65.

An additional pair of generally (2 shaped spaced parallel cross members 68 and. 69* interconnect tubes 45 and 46 and are clamped thereto as heretofore described. These C shaped cross members are directed upwardly relative to the tubes and provide the sliding support for the welding rectangular subframe W which, in a manner similar to the other subfrarnes, comprises a pair of spaced parallel rods 76 and 71 which are mounted for sliding movement parallel to the axes of the tubes 45 and 46. The rear end of rods 79 and 71 are interconnected by a cross member 73 to which they are rigidly secured, and the forward ends of these rods have the fixed welding head member 44 secured thereto, as aforedescribed. By reason of this sliding movement for welding subframe W, the same is constrained to move parallel to the axes of tubes 45 and 46 to thus assure that the wheels 30 are directed with precision along and parallel to the aligned and abutting nodes juxtaposed. upon the electrode pins 19.

Welding subframe W provides support for a longitudinally extending member 7 4 which. is secured in elevated position above this subframe by means of fore and aft members 75 and 76 which are secured respectively to head member 44- and cross member '73, this superstructure being removed in FIG. 3, and being disclosed in part in FlG. 11 wherein member 75 is disclosed as being secured to member 44 as by suitable fasteners 75a. A pair of vertically disposed members 77 depend from either side of member 74 to which they are secured and provide as at 78 a pivot support for a lever 79, the front end of which is pivotally secured as at 80 to the vertically movaule portion 39' of the welding head, aforedcscribed. The other end of lever head 79 has secured thereto on either side thereof a pair of vertically disposed depending members 81 which provide a pivotal support as at 82 for a cam follower wheel 83. Wheel 83 is mounted in cooperative relation to a cam 84 having rise and fall surfaces 85 and 86 which are spaced in accordance with the width of ribbon 15'. Cam 84 is supported on cross members 68 and 69 to which it is suitably extended and interconnected, as may best be seen in FIG. 3. By reason of this arrangement, sliding movement of the welding subframe W to sweep the wheels across the ribbon also causes, by reason of the coaction between wheel follower 83 and cam 84, a downward movement of the vertically movable cam head portion 39 with the result that the wheels 3t) first engage the aligned ribbon nodes and thereafter build up a desired contact pressure therewith as the spring assemblies 42 are compressed by further lowering movement of head member 39.

in the arrangement of the parts as disclosed in FIG. 4, the machine is set for welding only in the forward pass of wheels 30 over the core. To accomplish this, members 81 are mounted for pivotal movement about a pin 193 carried by lever 79, being yieldably biased to the upright position shown by a spring 192 which interconnects members 81 and member 74. A pin 194 carried by members 81 engages lever 79 to prevent counter clockwise movement of the members about pivot 193 when wheel 83 engages cam surface 85. Hence the wheel assembly is lowered as carriage W advances to move the welding head across the core. A coil spring 195 interconnecting lever 79 and member 74 raises the welding head as wheel 83 moves down the cam surface 86 at the end of the forward stroke. As the wheel engages cam surface 86 on the return stroke, members 81 are now free to move clocswise about pivot 193 as spring 192 is thereby tensioned. As a result, the welding head is not lowered on the return stroke.

When welding is desired on both the forward and return strokes of the welding head 19, members 81 are fixed to lever 79, this being accomplished by removing pin 194 and rotating members 81 counter clockwise until the same are aligned with lever 79 so that pin 194 may be reinserted to pass through an opening 196 therein. Members til being then locked to lever 79, engagement of wheel follower 83 with both cam surfaces 85 and 86 15 will cause lever 79 to tilt and thus lower the welding Wheels.

It will be understood that additional cams like cam 84 which are similarly mounted cooperate as with a cam follower switch 197 which may serve to switch the Welding current on and off as the wheels respectively engage and leave the abutting nodes. Similarly a second cam having several peaks may similarly be engaged by another cam follower switch to cause tack welding of the abutting nodes at spaced intervals therealong. Still another switch and cam arrangement may be similarly employed to direct cooling air to the wheels 30 during the passage of the welding current and to direct the air against the unwelded ribbon thereby to urge the same against the electrode pins preparatory to welding.

An arrangement for so directing the air is disclosed in FIGS. 11 and 12 wherein it may be seen that air from a source, not shown, is supplied by way of a flexible tube 198 to the inlet 198a to an air manifold in the form of a rigid tube 199. Depending from manifold tube 1% in spaced relation therealong is a plurality of air outlet tubes 2% from which the air passes in jets and strikes the ribbon to urge the same against the electrode pins. The air on being reflected from the ribbon strikes the wheels to cool the same, and to this end, the air is turned on before the welding wheels engage the ribbon and before the welding current is caused to flow.

Manifold tube 199 is secured at each end to an arm 201 which extends rearwardly and then upwardly to be secured as by a suitable fastener 202 to member 39, fasteners 292 being received in openings 203 on opposite sides of member 39. A pin 2% on one arm 201 mounts a coil spring 205 which is anchored on the other end thereof as on leaf spring 174. A lug 266 on this arm carries a stop screw 2il7 which engages adapter plate 145 to-limit movement of air outlet tubes 2% toward the wheels under tension of spring 2%5.

The ease of the free sliding movement of subframes I, S, E, and W is greatly facilitated by the use of linear bearings 72 which are employed within tubes 45 and 46, on shuttle slide members 59, and on cross members 65, 66, 63, and 69. Such linear bearings are well known and may be of any type suitable for the purposes such, for example, as those manufactured and sold by the Thomp son Ball Bushing Company Whose XA122026 linear bearings are particularly well suited for the purpose.

Referring now to FIGS. 3 and 4, it will be seen that a first pair of spaced rods 2% extend rearwardly from cross frame member 69 to which they are secured, each by a fastener block 299. A second pair of rods 210, disposed below rods 208, extend rearwardly from cross frame member 66 to which they are suitably secured. These rods are secured respectively to upper and lower plates 211 and 212 having bent and apertured portions to receive the same whereby the plates are secured to the threaded ends of the rods as by the nuts 213.

Extending between plates 211 and 212 and suitably secured thereto as by welding is an angle member 214. Three extensions or lugs 215 from the fore-to-aft leg of angle 214 serve as stops for carriage frames W, I and E, these respectively appearing from top to bottom in FIG. 4. Upper stop lug 215 coacts with a stop pin 216 adjustably threaded to cross beam 73 and secured thereto by lock nut 217, to thus limit the rearward movement of welding frame W. A similar stop pin 218, similarly adjustably secured to the forward side of beam 73, limits the forward movement of welding carriage W as pin 218 moves to engage fixed cross beam 69.

Similarly, cross beam 64 of the electrode pin frame E carries stop pins 219 and 220 fore and aft of the beam which respectively engage beam 66 and bottom stop 215 as the electrode supporting frame E moves fore and aft to insert and withdraw the electrode pins 19 from the cells of the core.

In the same manner, cross beam 54 of the supporting frame I for the indexing pins carries stop pins 221 and 222 fore and aft of the beam, these pins respectively engaging a plate 6% (FIG. 4) which interconnects cross beams 66 and 69 and intermediate stop 215, to thus limit the fore and aft movements of frame I as the indexing pins are withdrawn from the core and reinserted therein, respectively. As aforementioned, ribbon stops 96 on indexing pins are aligned at the extended ends thereof with the inner face of stripper bar 24 and this is accomplished through adjustment of stop pin 222 on cross beam 54.

Referring again to FIG. 5, it will be seen that shuttle member 59 is limited in its movements on rods 57 and 58 by fixed set screws 223 which are secured respectively to members 55 and 56. In addition, a pair of floating stop pins 22 and 225 are provided for the right and left sides of the machine, each having a crank arm 226 which terminates in a ball 227. Pins 224 and 225 are mounted for sliding movement in tubes 229 and 23%), respectively, which are secured as by welding to their associated members 55 and 56, these members having aligned openings through which the pins extend.

Each of tubes 229 and 239 is slotted longitudinally as at 231, and these slots terminate in a lateral slot 232, in order to accommodate movements of arms 226. Thus, arm 226 for pin 224, to reach the position shown in FIG. 5, would be moved to the left along slot 231, being extended at this time horizontally from tube 225 until slot 232 is reached. Arm 226 and ball 22'? are then moved downward to the position shown to thus lock pin 224 in a position to limit movement of member 59 completely to the right. The shuttling movement of member 59 is then restricted to engagement with pin 224 in movements to the right and engagement with stop pin 223 in movements to the left.

When the shuttling direction of the core is to be reversed, arm 226 for pin 224 is raised and moved to the right along slot 231, the pin then having a position as depicted for pin 225 in FIG. 5. With shuttling member 59 then positioned either in its center position or to the extreme right in contact with stop pin 22-3, pin 225 is moved to the right until its arm can be lowered into slot 232. This then places pin 225 into a position comparable to that depicted for pin 22:4 in FIG. 5 and this will then restrict further shuttling movement of member 59 to movements between pin 223 on the right and pin 225 on the left. The fine adjustments afforded by the set screws 223 and the like arrangement on the ends of pins 224 and 225 assures that member 59 and the indexing pins supported thereon will always be moved in exact increments corresponding to an integral multiple of the spacing between the cells.

Member 59 has mounted thereon, as by fasteners 233, a bracket 23% having forwardly extending apertured arms for receiving a pair of bolts 235 which are suitably secured thereto as by nuts, as shown. The ends of bolts 235 carry cable clamps 236, or the like, to which opposite ends of a single cable 237 are respectively secured in a well known manner. The cable from one clamp 236 passes over a pulley 238 mounted on member 5d, and then passes over a second pulley 239. The cable from the other clamp 236 passes over a pulley 244) which, together with pulley 239, is mounted on a bracket 241, in turn, secured as by fasteners 242 to member 55. From pulleys 239 and 240, the cable is directed rearwardly over pulleys 243, also pivotally supported on bracket 241, to a drum 244 (FIG. 3) about which it is wound in threaded grooves and to which it is suitably secured.

Sheave or drum 244 is driven thru a gear box 245 by an electric motor 246a, these elements together com prising a unit generally designated 246 which may be of any type suitable for the purpose such, for example, as the actuator manufactured by Lear, Inc. of Grand Rapids, Michigan.

The motor per se for such an actuator has a rated speed of the order of 20,000 rpm. and therefore incorporates a magnetic clutch to disengage the motor from the gear train in order to avoid over running due to the inertia of the motor armature. A brake is also incorporated which locks the gear train to the gear housing as do motor is disengaged from the gear train. Simi larly, the brake releases the gear train as the motor is energized and establishes a driving connection with the gear train through the magnetic clutch.

It is a feature of the cable drive for shuttle member 52?, however, that the same be moved into position against its stops before the drive motor is deenergized. This is accomplished by mounting the actuator unit for rotation yicldably about the axis of cable drum 24 and against the force of a U-shaped torsion rod spring 247, one end of which is secured to gear box housing as at 248 and the other end of which is secured to a mounting bracket 249, in turn, secured to cross beam i l by bracket By reason of this arrangement, when the member moves against one of its stops, further winding of the drum ceases as the cable tensions, and further rotation of the motor armature rotates the gear housing which has a pin arranged to engage the actuating button of one of two micro switches, not shown, depending on the direction of rotation of the gear case about he drum or actuator drive axis. A break-make switch combination in the micro switch thus actuated deenergizes e motor and the make portion of the switch combination serves as a sequence switch for initiating a followup function of the machine. Anoth sequence switch connected in series with the brealr portion of the other micro switch, when closed in the cycle of operations of the machine, will energize the motor for operation in the reverse direction until the gear box rotates sufl'iciently in the opposite direction to actuate the other micro switch and again deenergize the motor, the member 59, however, having meanwhile been-brought to a positive and precise stop at its initial position.

As safety precaution, drum preferably is driven from the gear box 245:" through engaging clutch lates 25% and 25-32%, plate 2% bei secured to the output of the train and plate 255i being suitably secured to drum These clutch plates are yicldably urged toward each other with a pressure determ' by the compression of a laterally otrset washer type spring 252 which is interposed between pressure plates 2253 and 254 Plate Zs l bears freely rotatively against the gear case coaxially with clutch plates rat but i not connected to the train. Sin ilarly, a bolt passes i ccly thr lgll drum 244, clutch plates and 253 gear box ciw and of pul' ys i which r rect opposite ends of the cable fore and at; of beam for securing in manner aioredescribcd to plate 629:: (FIG. 4) as at 2% and'to as at Pulleys are supported on a 5, in turn, secured to the underside of beam Actuator assembly is supported on cross beam 64 and its cable 2645 ext to and fore and aft from a pair of: pulleys as" supported in a bracket 2 8, in turn, secured. to beam ti l, the fore end of cable 266 being 18 secured as at 2&5 to plate 69a and the aft end being secured as at 27b to angle 214.

Actuator assembly ass is supported on cross beam 54 and its cable 271 extends to and fore and aft from a pair of pulleys 2'72 supported in a bracket 2'73, in turn, secured to beam 54, the fore end of cable 22 i being secured as at to plate 69a and the aft end thereof being secured as at to angle 2M.

Referring now to Fl-GS. 20 to 22 for further details of construction of actuator unit 246, it will be seen that drum 24 5- is threaded on the periphery as at 276 to receive and retain cable 237 thereon. in addition, the drum periphery has a milled slot 277 which is intercepted by a screw 273, the arrangement thus being such that the cable may be suitably secured by the screw to the drum. The drum is recessed as at 279 to freely receive the head of bolt 25 5, and the drum has a central open- Zaltl tor freely passing the shank of the bolt. The central opening is enlarged as at to provide a hearing surface for receiving a hub 23?. on clutch member 2%. For purposes oi. this affording a suitable bearing therebetween, drum 2M- and hub preferably are re spcctively formed of materials suitable for the purpose such for example, as brass and cast iron.

Drum 244 has a hub which interfits with clutch member 251 which is in the form of a washer of mate- ".l suitable for the purpose such, for example, as Micarta. The was ier is suitably bonded to the drum and projects somewhat beyond the f ce present of hub no; LO an clutch face to clutch member which, as aiorcdescribed, is formed of a material suitable for the purpose such, for example, as cast iron.

Clutch member 25 .3 is suitably secured, as by rivets (not shown), to an internally splined member adapted to receive the externally splined output member 285 of the gear train housed in gear box lid-5, thereby to form a driving connection therewith. Motor 246a (FIG. 3) is secured as by bolts to the underside of gear box 2-45, as seen in MG. 26, and a pinion having driving connections with the motor armature engages and meshes with a gear of the gear train when the motor is thus mounted on the gear box. The magnetic clutch forms part of these driving connections, and the motor brake locks and releases the pinion, respectively, as the magnetic clutch releases and operatively connects the armature and pinion.

The hub portion 285 of member 2854 is received within a bearing which, in turn, is suitably secured to, and mounted within an opening provided therefor in member 24% of the mounting bracket or frame. Frame member 249 is secured as by welding to a frame member 237 which has an angular portion having openings 289 which are adapted to be aligned with openings 2.99 in plate 256 whereby frame plates or members 2?? and 256 may be secured together as by fasteners Ztll (FIG. 20), Frame members 249, and 256, thus assembled, provide a rigid frame by which the actuators 246, 253, 259 and 260 (MG. 3) may be secured to the machine frames individual thereto.

Plate 256 has an opening which lies along the drive axis of the actuator 24 6, and this opening receives a bearing 2.92, vhich is suitably secured to plate 256. Bearing 292 suitably journals the hub 253 of pressure disc plate 253 which has a central opening 294 for freely passing the shank of bolt Each of pressure disc plates 25.3 and has a central opening which receives spline memher 285" such that these plates are adapted to be supported, and to rotate freely on the spline member. The end face of the hub of pressure plate 2% engages and forms a suitable end bearing with a surface (not shown) provided on the gear box. The opposing faces of the pressure plates are undercut as at to seat spring washer 252 therewithin and between the plates, washer 252 also being freely slidable on the spline member 255.

By reason of the foregoing construction and arrangement of the parts as depicted in exploded View 21, the

39 same may be assembled, and nuts 257 tightened on bolt 255, preferably employing a Micarta washer 309, or the like, to seat in the bottom of recess 279, and a metal washer 310 to bear against the end face of hub 2%. Tightening of nuts 257 compresses spring washer 252 and thus develops pressure between clutch plates 25% and 251, while still providing for the free drive of the gear train output member 285 from the motor, and hence the free drive of the drum 244-, while also providing for the free relative rotation of the gear box 245 and mounting frame therefor about the drive axis of the actuator, namely, about the axis of bolt 255 and drum 244.

In order to restrict and yieldably limit the relative movement between the gear box 24-5 and its mounting frame 249, 287 and 256, torsion rod spring 247 is provided. This spring, as may best be seen in FIG. 20 is generally U shaped in configuration and has the extremities 297 and 2% of its legs bent at right angles, as best seen in FIG. 21. Leg extremity 297 is received in an Opening 299 in mounting plate 249 and, although slidably movable therein, makes a snug fit therewith. Leg extremity 293 has a collar 36%) secured thereto which limits the extent of movement of the same into an opening 248 provided therefor in the gear box. Another collar 3% positioned on and secured to leg 298 on the opposite side of the gear box serves to retain the spring 247 in position thereon. As a result of this yieldable mounting arrangement, the legs of U spring 247 tend to spread or move together yieldably as gear box 245 tends to move counter clockwise or clockwise, respectively, about the drum axis, as is best viewed in FIG. 20, this movement, of course, being with respect to the frame members 249, 287, and 256 which are presumed to be secured against rotation.

Gear housing 245 has a pin 301 suitably secured thereto which extends through a considerably larger diameter opening 302 provided in plate 256. Similarly an enlarged, coaxially disposed, counterpart 3% of this pin extends through a clearance opening 394 provided therefor in plate 249. By reason of this clearance arrangement, the gear housing and pins 3M and 393 have limited freedom of movement therebetween suflicient for the selective actuation of a pair of identical micro switches 305 and 3% which are respectively mounted as by brackets 3M and 368 to plate 256 in opposed relation with respect to pin s01.

Brackets 307 and 308 are identical except for upturned and opposed portions 311 and 312, which thus makes one bracket a right and the other a left. The brackets are pivotally secured as by screws 313 to plate 256 and clamped in position, adjustably thereon, by the screws 314 which pass through elongated slots 315 in the brackets. Switches 305 and 3496, in turn, being secured as by screws 316, to their respective brackets, are adjustably positioned thereby such that the actuating buttons 217 of the switches are adapted to be engaged by pin 301 selectively in accordance with the predetermined relative positions of rotation of the gear housing 245 and its mounting frame, as herein before described.

Each of the micro switches 305 and 306, which are conventional, has three terminals 218, 219 and 220 which connect to a pair of internal, normally open contacts and a pair of internal, normally closed contacts which together constitute a make-break switch combination, as aforedescribed, one of the terminals being common to both the make and the break pairs of contacts.

From the foregoing, the operation of the core fabricating machine as herein disclosed should now be fully apparcot and, likewise, the features and functions of thewelding, electrode, and indexing heads and of the framewor; and subframes in assuring the desired precision of movement of the welding head and electrode and indexing pin assemblies should also be apparent to thus fulfill the aforestated objects and features of the invention. It will be apparent, for example, that the modular components of the machine are readily adapted for replacement and repair and that the mechanisms of the machine lie largely to the rear of the ribbon and core being fabricated to thus place the fabrication process substantially in full view of and available for ready access of an operator in attendance at the machine. The open skeletal framework, moreover, not only constitutes a light weight structure, but presents the moving mechanisms and parts in full operative surveillance and for ready access in case of need for repairs.

While the invention here involved has been embodied in a single disclosed preferred form, it will be apparent to those skilled in the art, to which the invention most closely relates or appertains, that the same may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present embodiment of the invention is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Having thus described our invention, what we claim is new and useful and desire to secure by Letters Patent is:

l. In a drive system, a stop member, a driven member, drive means including a yieldable driving connection with said driven member for moving said driven member to position the same precisely and positively against said stop member, means for deenergizing said drive means in response to predetermined yielding of said driving connection when the drive means has positioned said driven member against said stop member, and means effective on deenergization of said drive means for locking said driving connection and thereby holding the driven member in position against the stop member.

2. In a drive system, a stop member, a driven member, a motor actuator including a yieldable driving connection between the motor and said driven member for moving said driven member to position the same precisely and positively against said stop members, said actuator having switch means for controlling energization of the motor, said actuator having means for actuating said switch means to deenergize the motor in response to predetermined yielding of said driving connection when said driven member moves into position against said stop member, and said actuator having means effective on deenergization of the motor for locking said driving connection and thereby holding said driven member against the stop member.

3. In a drive system, a stop member, a driven member, rotatable drive means including amotor for moving said driven member to position the same precisely and positively against said stop member, said drive means having rotor and stator parts relatively rotatable about a common' drive axis, a first driving connection between said rotor part and said driven member, a second driving connection between said motor and said rotor part and including said stator part, means for yieldably restricting rotation of said stator part about said drive axis whereby upon energization of said motor said driven member is moved by said rotor part to said stop member and said stator part is rotated as the driven member is stopped, switch means actuable by said stator part to deenergize said drive means upon predetermined yieldable rotation of the stator part about said drive axis, and means effective on deenergization of said drive means for locking said second driving connection and said stator part thereby to'hold said driven member in position against said stop member.

4. In a drive system, a stop member, a driven member, a motor actuator having a rotatable output drive member, a first driving connection between said output drive member and said driven member to drive the same precisely and positively to and against said stop member, means mounting the actuator for limited rotation yieldably about the axis of said output drive member, a second 21 driving connection between the motor and said output drive member and including said actuator mounting means, switch means actuable by said actuator to deenergize said motor upon rotation of the actuator to a predetermined position when the driven member has engaged the stop member, and means effective on deenergization of said motor for locking said second drive con nection and said actuator in said predetermined position.

5. In a drive system, a stop member, a driven member, a motor actuator comprising a motor, a cable drum, and a gear train for driving said drum form the motor, means mounting said motor actuator for rotation about the axis of said drum, means for yieldably limiting said rotation of the actuator, switch means secured to said mounting means and actuable by said actuator to dcenergize said motor when the actuator has rotated to a predetern'iined position, cable driving connections between said drum and said driven member to drive the same to and against said stop member when the motor is energized, said actuator having means operative as the motor is deenergized for locking said gear train thereby to hold the actuator in rotated position thereof.

6. In a drive system, a pair of spaced stop members, a driven mom er mounted for movement to and against said stop members selectively, a motor actuator comprising a reversible motor, a cable drum, and a gear train for driving said drum from the motor, means mounting said mo tor actuator for rotation in either direction about th axis of said drum, means for yieldably limiting said rotation of the actuator, a pair of switch means actuable alternately by said actuator as the same rotates in opp "to directions between predetermined positions, each of said pair of switch means having a first contact means for effecting rotation of the motor in a direction opposite to that effected by the other wt en the motor is energized and having a second contact means for deenergizing the motor as the actuator rotates to actuate the other of the switch means, and a cable wound about and secured to said drum and secured at the ends thereof to opposite ends of said member so as to drive the same to and against said stop members selectively in accordance with the direction of rotation of the drum, said actuator having means operative as the motor is tie-energized for locking said gear train to hold the actuator in rotated position thereby to keep said cable tensioned and said driven member in position against the stop member 7. in a drive system as in claim 6, said actuator motor having means for disconnecting its armature from the gear train upon decnergization of the motor concurrently with said lockingof the gear train.

8. In a drive system as in claii 7, said actuator having a clutch interposed between said drum and said gear train and means disposed coaxially therewith for adjusting the pressure between engaging surfaces of the clutch.

9. in a drive s stem in claim 8, said gear train having a hollow output shaft operativcly connected at one end thereof to said clutch, said clutch pressure adjusting means comprising a bolt extended through said drum, clutch and gear train output shaft, a laterally oifset spring washer on said bolt, a pair of pressure plates disposed on said bolt on opposite sides of said spring washer, one of said pressure plates being iournalied on the other end of said output shaft, and threaded fasteners on the bolt for compressing said spring washer between said pressure plates as the fasteners are tightened on the bolt there by to increase the pressure between the engaging surfaces of the clutch.

10. a drive system as in claim 6, said means for in accordance with the direction of rotation of the actuator relative to said mounting means therefor.

ii. In a drive system as in claim 6, said first and second contact means of said pair of switch means being operatively connectable electrically in said drive system to cite-ct sequential movements of said driven a ember between said pair of spaced stop members.

12. in a drive system for fabricating honeycomb core, a plurality of indexing pins insertable into the cells of the core for shuttling the same in a direction laterally of the pins, a pair of stop means for restricting said shuttling movement of the pins between an initial position of the pins and a shuttled position thereof spaced by multiple increments of the spacing between cells, movable means mounting said pins for movement and in a closed-loop rectangular path comprising withdrawal of the pins from the core in said shuttled position thereof, return shuttling movement of the pins relative to the shuttled core, and reinsertion of the pins into the core in said initial positio reversible drive means including a yieldable driving connection with said pin mounting means for moving said pin mounting means to selectively position the same precisely and positively against said pair of stop means, means for deenergl 1g said drive means in response to predetermined yielding of said driving connection when said drive means has positioned said pin mounting means against either one of said stop means, and means effective on deenergization of said drive means for locking said driving connection thereby holding said pin mounting means in position ag inst said one of the stop means until the drive means is reversely energized to move the pin mounting means toward the other of the stop means.

13. in a drive system for fabricating honeycomb core, a plurality of indexing pins insertable axially into the cells of the core and adapted when inserted therein to shuttle the core in a direction laterally of the pins, a first stop means for restricting said core shuttling movement of the pins from an initial. position thereof to a shuttled position of the pins spaced from said initial position by multiple increments of the spacing between cells, a second stop means for restricting axial movement of the pins from said shuttled position thereof to a position i. l withdrawn from ti o cells of the core, a third stop in for restricting return movement of the pins from said withdrawn position thereof to a return shuttled position of the pins in axial alignment with the initial position thereof, a fourth stop means for restricting axial movement of the vpins from said return shuttled position thereof to said initial position, a first ,novable means mounting said pins for said shuttling movements thereof, a second movable means having said first mounting means movably supported thereon for mounting the pin for s d axial movements thereof, a first reversible drive means eluding a first yieldable driving connection with said first pin mounting neans for moving said first mounting means to selectively position the same precise and posh tively against said first and third stop means, a second reversible drive means incltdirn a second yieldable driving connection with said second pin mom moving said second pin morn 'lg means to sclec ive y position tl e same precisely and positively against sai secend and fourth stop means, a first switch means operable by said first drive means tic-energizing the same in re sponse to predetermined yielding of said first drive connection when said first drive means has positioned the first pin mounting means against either one said first and third step means, a second switch means operable by said second drive means for deenergizing the same in response to predetermined yielding of said second d 'ving connection when said second drive means has positioned. the second pin mounting means against either one of said second and fourth stop means, means effective on deenergization of the first drive means for locking said first drive connection to hold said first 13in mounting means against said one of the first and third stop means until ting mean for i 

1. IN A DRIVE SYSTEM, A STOP MEMBER, A DRIVEN MEMBER, DRIVE MEANS INCLUDING A YIELDABLE DRIVING CONNECTION WITH SAID DRIVEN MEMBER FOR MOVING SAID DRIVEN MEMBER TO POSITION THE SAME PRECISELY AND POSITIVELY AGAINST SAID STOP MEMBER, MEANS FOR DEENERGIZING SAID DRIVE MEANS IN RESPONSE TO PREDETERMINED YIELDING OF SAID DRIVING CON- 